Comment 7 for bug 1370602

There is currently no mechanism for a package maintainer script to automatically detect that you added additional ports and apply this change to the new configuration file in a major upstream release update.

If you have a customised configuration file, then when you upgrade you should get a prompt asking you to update your customisations to match the new configuration file. If you don't, or you upgrade non-interactively, then the old configuration file will remain because we don't want to overwrite your customisations. That will cause the daemon to fail to start.

When configuration file syntax changes between releases, there's no other real path that we can follow unless upstream provides some kind of automatic way to update previous configurations.

I'd love to know how other distributions solve this problem. Debian/Ubuntu make some use of ".d" directories to try and help with this, and specific improvements might be able to be made, but I'm not aware of any solution to the general problem.